net.connect: Propagate last error message from resolvers
Previously it would only say "unable to resolve server" for all DNS
problems. While "NoError in A lookup" might not make much sense to
users, it should help in debugging more than the previous generic error.
Friendlier errors will be future work.
--- a/net/connect.lua Fri Nov 12 13:30:39 2021 +0000
+++ b/net/connect.lua Fri Nov 12 16:52:55 2021 +0100
@@ -35,9 +35,9 @@
p.target_resolver:next(function (conn_type, ip, port, extra)
if not conn_type then
-- No more targets to try
- p:log("debug", "No more connection targets to try");
+ p:log("debug", "No more connection targets to try", p.target_resolver.last_error);
if p.listeners.onfail then
- p.listeners.onfail(p.data, p.last_error or "unable to resolve service");
+ p.listeners.onfail(p.data, p.target_resolver.last_error or p.last_error or "unable to resolve service");
end
return;
end
--- a/net/resolvers/basic.lua Fri Nov 12 13:30:39 2021 +0000
+++ b/net/resolvers/basic.lua Fri Nov 12 16:52:55 2021 +0100
@@ -52,12 +52,17 @@
local dns_resolver = adns.resolver();
if not self.extra or self.extra.use_ipv4 ~= false then
- dns_resolver:lookup(function (answer)
+ dns_resolver:lookup(function (answer, err)
if answer then
secure = secure and answer.secure;
for _, record in ipairs(answer) do
table.insert(targets, { self.conn_type.."4", record.a, self.port, self.extra });
end
+ if answer.status then
+ self.last_error = answer.status .. " in A lookup";
+ end
+ else
+ self.last_error = err;
end
ready();
end, self.hostname, "A", "IN");
@@ -66,12 +71,17 @@
end
if not self.extra or self.extra.use_ipv6 ~= false then
- dns_resolver:lookup(function (answer)
+ dns_resolver:lookup(function (answer, err)
if answer then
secure = secure and answer.secure;
for _, record in ipairs(answer) do
table.insert(targets, { self.conn_type.."6", record.aaaa, self.port, self.extra });
end
+ if answer.status then
+ self.last_error = answer.status .. " in AAAA lookup";
+ end
+ else
+ self.last_error = err;
end
ready();
end, self.hostname, "AAAA", "IN");
@@ -80,12 +90,17 @@
end
if self.extra and self.extra.use_dane == true then
- dns_resolver:lookup(function (answer)
+ dns_resolver:lookup(function (answer, err)
if answer then
secure = secure and answer.secure;
for _, record in ipairs(answer) do
table.insert(tlsa, record.tlsa);
end
+ if answer.status then
+ self.last_error = answer.status .. " in TLSA lookup";
+ end
+ else
+ self.last_error = err;
end
ready();
end, ("_%d._tcp.%s"):format(self.port, self.hostname), "TLSA", "IN");
--- a/net/resolvers/service.lua Fri Nov 12 13:30:39 2021 +0000
+++ b/net/resolvers/service.lua Fri Nov 12 16:52:55 2021 +0100
@@ -20,6 +20,9 @@
self.resolver = basic.new(unpack(next_target, 1, 4));
end
self.resolver:next(function (...)
+ if self.resolver then
+ self.last_error = self.resolver.last_error;
+ end
if ... == nil then
self.resolver = nil;
self:next(cb);
@@ -57,12 +60,15 @@
if #answer == 0 then
if self.extra and self.extra.default_port then
table.insert(targets, { self.hostname, self.extra.default_port, self.conn_type, self.extra });
+ else
+ self.last_error = "zero SRV records found";
end
ready();
return;
end
if #answer == 1 and answer[1].srv.target == "." then -- No service here
+ self.last_error = "service explicitly unavailable";
ready();
return;
end
@@ -71,6 +77,8 @@
for _, record in ipairs(answer) do
table.insert(targets, { record.srv.target, record.srv.port, self.conn_type, self.extra });
end
+ else
+ self.last_error = err;
end
ready();
end, "_" .. self.service .. "._" .. self.conn_type .. "." .. self.hostname, "SRV", "IN");